First isolated from bovine brain, hsc70 is a member of the ubiquitous 70kD class of molecular chaperones believed to be involved in in vivo protein folding. To date, no crystallographic or solution structure has been determined of hsc70 or of it's C-terminal peptide binding domain. The only structure of this class of proteins was solved by X-ray methods for the N-terminal ATPase domain of hsc70. The present work will attempt to produce the first structure of the C-terminal peptide binding domain. Of general interest is the nature of the binding interactions that permit hsc70 to recognize a wide variety of protein substrates, including the S-peptide of ribonuclease A and the light chain of clathrin. Based on sequence homology, it has been proposed that the C-terminal domain of hsc70 is structurally analogous to the MHC class I peptide binding motif. This hypothesis can be tested from the secondary structure that should be obtained at a relatively early stage in this project.